The present invention relates to 2,5-diketo-D-gluconic acid reductase (hereinafter, abbreviated to as 25DKG-Rase) and its production.
The disclosed enzyme has an action of catalyzing, in the presence of reduced nicotinamide adenine dinucleotide phosphate (abbreviated to as NADPH), reduction of 2,5-diketo-D-gluconic acid (abbreviated to as 25DKG) to 2-keto-L-gulonic acid (abbreviated to as 2KLG), the precursor of vitamin C. It also has an action of catalyzing reduction of 5-keto-D-fructose (abbreviated to as 5KF) to L-sorbose.